Samuel kbaus



" fNlTED 1i STATES PAT NT EIGE. 7

SAMUEL KRAUS, OE' EW YORK, N. Y., ASSIGNOR TO THE EAGLE PENCIL COMPANY, or SAME PLACE.

couo'lio LEAD FOR PENCILS'.

SPECIFICATION forming part of Letters Patent No. 316,373, dated April 21, 1885.

Application filed March 5, 1885. (No specimens.)

To all whom it may concern..-

Be it known that I, SAMUEL KRAUS, of the city, county, and State of New York, have invented a certain new and useful Improvement in Colored Leads for Pencils, &c., of which the following is a specification.

My invention has relation to what are commonly known in the art of lead-pencil-making as colored leads or crayon leads- 10 that is to say, blue, white, red, green leads, and the like, as contradistinguished from the ordinary graphite pencil-lead.

In making colored lead heretofore it has been the practice to mold or press it from a I 5 composition consisting of the colorred,blue, or the likea basesuch as kaolin-and a binding medium or gumsuch, for instance, as gum-tragacanth. This process of manufacture is not only tedious and expensive, but is uncertain to some extent in its results, and often results in the production of an inferior article. The composition, owing to the gum which it contains, cannot be baked, but must v simply be dried, and the gum affects often- 2 5 times the quality of the article.

It is the object of my invention to remove these obstacles and to produce a colored lead which can be made as easily and inexpensive- 1y as the ordinary graphite pencil-lead, and

which shall possess equal efficiency. To obtain this result it is requisite to bake the colored composition lead; but to do this it is indispensable that the gum ordinarily, used should be dispensed with, because the effect of 3 5 the baking operation would be to entirely burn and destroy it; and it is also requisite to employ colors which will Withstand without deterioration the heatrequisite for the baking operation. Among such colors, which 0 may be named by way of example, are ironred, ultramarine, burnt sienna, Indian red, chrome and mineral yellow, (I use a mixture of the two for the production of a yellow, inasmuch as the chrome-yellow alone will not withstand so well the heat,) and what is known as Victoria, permanent, or lump green. I use as a base, preferably, a mixture of talc or soapstone and potters clay, and to this base I add the requisite quantity of color of the shade required, together with a little I graphite, if it be required to modify or darken the shade.

For whatis known in the trade as a medium soft lead, the ingredients may be taken in about the following proportions: coloringmatter, (of the character above specified,) ten pounds; talc or soapstone, five pounds; potters clay, ten pounds. I here remark that by increasing or decreasing the proportion of potters clay the lead produced will be ren- 6) dered proportionately harder or softer. These ingredients are mixed with water to a paste. and are then ground, so. as to be finely reduced and intimately mixed and brought to the condition of asmooth homogeneous paste. Then by means of a presssuch as employed in the manufacture of pencil-leads and well known to those skilled in the art to which my invention pertainsthe composition is molded or brought to the shape of a pencil-lead. In 0 this condition it is allowed to thoroughly dry. After drying-it is baked. For this purpose the furnace or baking chamber is preliminarily raised to about a bright-red heat, the dried colored lead is placed therein and allowed to 5 remain about ten minutes, or until it is heated to a dull-red heat. It is then withdrawn and allowed to cool. In this condition it has the characteristics of a slate-pencil, and is still unfit for use as a colored pencil-lead. The final operation is to boil it in fat or oil-such, for instance, as stearine, which I find on the whole productive of the best results. It is immersed in the boiling stearine, and is there allowed to remain for twenty minutes, or thereabout. This last-named operation changes the characteristics of the article and converts it into a pencil-lead which is quite as good as and in some respects superior to the ordinary colored lead or crayon hitherto made. 3

One great advantage is, that my colored lead can be made of as small diameter as the ordinary graphite pencil lead without any more danger of breaking when in use, which is not feasible with colored leads as ordinarily manufactured. Another advantage is, that marks made by it can be erased without smearing or soiling the paper, which is not the case with ordinary colored leads.

Having described my improvement and the best way now known to me of carrying the 2 The improvement in the manufacture of same into efi'ect, I wish it to be understood coloredpencil-leads, consisting in molding the that I do not restrict myself to the particular same from a composition of the kind herein- 15 details hereinbefore set forth illustrative of before described,drying and baking the molded 5 the improvement, for the same can be conarticle, andsubsequentlyboiling it infator oil, siderably varied without departure from the substantially set forth. I principle of the invention; but Intestimon'y whereof I have hereunto set What I consider to be new and of my own my hand this 4th day of March, 1885'.

invention is- SAMUEL KRAUS. 1o 1. A colored pencil-lead made and possessfi itnessesz 1 ing the characteristics substantially as here- J 0E W; SWAINE,

inbefore set forth. LEOPOLD ANSBAOHER. 

